In the absence of an ideal treatment for chronic pain associated with osteoarthritis in dogs, there is interest in the potential effect of cannabinoids. The objective of this placebo-controlled double-blind cross-over study was to evaluate the efficacy of cannabidiol (CBD) oil in dogs with multi-joint osteoarthritis. Eleven client-owned dogs with radiographically confirmed evidence of osteoarthritis were recruited. Dogs randomly received CBD oil twice daily (2 mg/kg) or placebo oil for 4 weeks followed by a 2-week washout period between treatments. Veterinary assessment of lameness and response to manipulation as well as owner questionnaires (Canine Brief Pain Inventory [CBPI], Hudson activity scale) were completed at weeks 0, 2 and 4 for each treatment.
Chemistry and CBC were performed at each visit and potential side effects were monitored throughout the study. CBPI and Hudson scores showed a significant decrease in pain and increase in activity at week 2, with only significant increases in activity at week 4 for CBD treatment (P<=.01). No major side effects were reported by the owners. Alkaline phosphate (ALP) increased over time for 8 dogs while receiving CBD oil, reaching significance at week 4 (P<=.01).
Until further long-term safety data are obtained, liver enzyme values should be routinely monitored while dogs are receiving cannabidiol treatment. This pilot study, though short in nature, suggests that CBD oil may help increase comfort and activity in dogs with osteoarthritis.